如何知道xpath是否存在

Question

你能帮我解决这个问题吗

如果xpath不存在，我如何知道并处理这个

喜欢……如果不存在，就做这个，如果存在，就做那个

谢谢大家。

const puppeteer = require('puppeteer');
(async () => {
// set some options (set headless to false so we can see 
// this automated browsing experience)
let launchOptions = { headless: false, args: ['--start-maximized'] };
const browser = await puppeteer.launch(launchOptions);
const page = await browser.newPage();
// set viewport and user agent (just in case for nice viewing)
await page.setViewport({width: 1366, height: 768});
await page.setUserAgent('Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/78.0.3904.108 Safari/537.36');
// go to the target web
await page.goto('https://www.lamudi.co.id/newdevelopments/');
// wait for element defined by XPath appear in page
await page.waitForXPath("(//span[@class='CountTitle-number'])[1]");
// evaluate XPath expression of the target selector (it return array of ElementHandle)
let elHandle = await page.$x("(//span[@class='CountTitle-number'])[1]");
// prepare to get the textContent of the selector above (use page.evaluate)
let lamudiNewPropertyCount = await page.evaluate(el => el.textContent, elHandle[0]);
console.log('Total Property Number is:', lamudiNewPropertyCount);
// close the browser
await browser.close();
})();

喜欢……如果不存在，做这个，如果存在，做那个…

Answer 1

你可以试试下面这些吗?

----
----
let elHandle = await page.$x("(//span[@class='CountTitle-number'])[1]");
if(typeof elHandle === 'undefined') {
console.log("it is not defined yet, do something");
} else if (elHandle.length > 0) {
console.log("you have a greater than zero length array, do something");
}
----
----

希望能有所帮助。